How We Monitor Water Quality This Summer in Downtown Vancouver
By Imogene Broberg-Hull
Safe to say no one saw 2020 unraveling the way it did. Our Vancouver Monitoring Program was put on hold in late March because of, well, you know what. But we are back! Things just look a little different.
To fill you in...
During the summer months (May to October), Fraser Riverkeeper would normally monitor water quality every week at three False Creek locations – Olympic Village, Brokers’ Bay, and Vanier Park. This year we are shifting the focus. Due to limited staff and volunteer capacity during COVID-19, we have reduced our water sampling to just Olympic Village. A small team of devoted volunteers and I (Imogene) will carry out the sampling for the remainder of the summer season.
Why just Olympic Village?
We have chosen to focus on Olympic Village because it has some of the worst historical water quality in Greater Vancouver. While Brokers’ Bay and Vanier Park typically pass water quality tests, Olympic Village fails often. It is important that we continue to monitor the area because this part of False Creek is heavily used by Vancouverites for a variety of recreational purposes and with consistent data, we can help support and implement long-term initiatives to clean up False Creek.
Who monitors the water?
With the help of a few experienced volunteers who will collect water samples weekly, I (Imogene) am able to process and analyze the water samples. We’re keeping the volunteer group small this summer to minimize exposure during COVID-19. Since I am new on the job, I thought I’d share my experience learning to monitor our waters. I heard teaching is the ultimate form of learning, after all.
What are you sampling for? And why?
When we sample and process water, we are measuring a variety of water column properties that together give us an overall look at the health of the water in that area. The primary indicator we use to determine whether a sampling site has “passed” or “failed” is e.coli level. E.coli, or Escherichia coli is found almost everywhere - from the food in your fridge to the naturally occurring bacteria in your own intestines. We really couldn’t function without it. However some of the strains of E.coli that end up in our water are bound to make us sick. We also measure properties like total coliform counts, Ph level, turbidity, salinity, dissolved oxygen and many more. To supplement that data, we collect environmental observations on physical characteristics, like whether or not there is litter or if people are out and about on the water. We do all this to track the weekly changes in water quality at our sites, and ultimately to ensure healthy water quality for both the ecosystem and our recreational activities.
So, how do you sample water?
Now for the fun stuff. To sample water in False Creek, the team needs five main things: Whirlpaks, a sampling pole, a cooler, something called a Secchi disk, and a YSI.
Whirlpaks are strong little plastic tubes we dunk into water to collect a 100ml sample at each of the five sample sites. We label each whirlpak with a special code to help us identify the location and time.
A sampling pole is a fairly self-explanatory device. It is a long pole with a contraption on the end that whirlpaks attach to. These help us reach the water at hard-to-reach locations or when it’s low tide!
A cooler is essential for keeping the samples cool while we trot from one sample site to the next.
A Secchi disk is an ancient looking thing (OK, it’s from 1865) that is used to measure water transparency or turbidity (the cloudiness).
Image: Pentairaes
And lastly, the YSI - the opposite of ancient. The YSI is a handheld digital sampling system that we submerge in the water to immediately measure Ph level, conductivity, dissolved oxygen, temperature, and more.
When we’re out sampling water, we’re also recording environmental observations, taking note of the surroundings and the type of litter that might be there, and interacting with curious citizens.
How do you process the water samples?
Once we’ve scooped up all our water samples and safely stored them in our cooler, we bike them to our lab on Granville island. The first thing I do is turn on the incubator and measure the temperature of the “temperature blank” - a whirlpak full of water that stays in the cooler. The purpose of the temperature blank is to monitor the temperature of the cooler. Samples should be as cool as or cooler than the body of water they came from.
We use a monitoring system called IDEXX to measure e.coli and total coliforms. The IDEXX system is a standardized method for quantifying the most probable number (MPN) of e.coli and total coliforms in water samples. The are four important steps to IDEXX processing: Colilert, Quantitrays, sealing the trays, and putting them in the incubator
I open up each whirlpak very carefully and, without touching any part of the inside, I empty a chemical called Colilert into each whirlpak, close up the whirlpak, and make sure all the powder is dissolved. Colilert is a powder containing chemicals that get metabolized by pathogens in water samples and make them obvious to see!
I then label a quanti-tray for each sample. Quanti-trays divide the sample into equal portions, which simplifies the statistical analysis later. Propping the tray open with one hand and carefully holding the colilert-ed sample in the other, I pour the liquid into the tray.
I feed the now full tray into the quanti-tray sealer, a large device that uses heat to seal the tray closed.
I place all the sealed trays into the incubator, which is now at a steamy 35℃. This is where the samples remain for the next 24 hours.
The steps involved in water sample processing. Colilert Image: Webber Scientific
How do you analyze the results? And what do they mean?
Analyzing the samples and tabulating results is a reward for the previous day’s work. I come back to the lab 24 hours after the quanti-tray samples are placed in the incubator. Since the IDEXX system can measure both total coliform and e.coli, we count both. However, e.coli is the number I’m looking out for, as the quantity of e.coli will determine whether the site passed or failed.
By the time I look at the quanti-trays, most of the wells (little cubes) will have turned yellow, indicating the near inevitable presence of total coliforms (TC) during warmer months. Total coliforms refers to a vast umbrella group of bacteria. All yellow wells receive a dash. Next, I place the quanti-tray beneath ultraviolet light (see image below). If there is a fluorescent well, that indicates e.coli - an X goes there. The glowing is caused by a chemical (with a very long name) in colilert, which is metabolized by an enzyme (β-glucuronidase) in e.coli during incubation.
I then record the number of small and large wells with dashes and X’s. Using this IDEXX chart, I find the number with the right ratio of small vs. large wells for both TC and E.coli, and record the most probable number (MPN) of bacteria for each sample site. I use these numbers to average out the MPN of all five samples and calculate the geomean for that location. If any of the samples have an mpn that exceeds 400 e.coli/100ml, the entire sample location automatically fails.
All this data goes into a large excel spreadsheet, which uploads to the Olympic Village page on Swim Guide. Fraser Riverkeeper also uploads our data results to our website results page.
Left: Hugging the quanti-trays, Top Right: identifying E.coli, Bottom Right: Entering data
My experience
What is the most challenging part?
If you asked me last week, I’d probably say that the most challenging part of water sampling and processing is ensuring I do not touch the inside of the whirlpaks or quanti-trays during various maneuvers. Simply knowing I shouldn't touch the inside makes it more tempting. However, this week’s challenge blew that out of the water. The biggest challenge I've faced so far has been learning to dilute a sample that spilled. Here’s what happened: a sample lost about 15ml of water en route to the lab. Since the sample didn’t have enough water to fill a quanti-tray, the only option at that point was to dilute the sample with distilled water and factor in that ratio later when it came to analyzing the results. Thankfully Elise Mackie, water scientist extraordinaire and Water Stewardship Specialist at Swim Drink Fish, came to the rescue via video chat to virtually hold my very sanitized hand through the process. If pouring a full whirlpak into the quanti-tray was a careful medical procedure, avoiding the sides of the whirlpak with the pipette dispenser full of water felt like a brain surgery. However, the challenge of learning to dilute samples made me a lot more confident doing all the things that I’ve been timid about in previous weeks.
Practicing using a Pipette with Elise on a video call
What are the best parts?
As much as I grumble about my own fear of spilling the whirlpaks or accidentally touching the inside, these moments are my favorite part. A lot of activities in life, I have to say, can be done with your mind elsewhere. In other words, I can be a space cadet. I think that is why I’m so drawn to activity that requires all my attention and care. It is sort of like meditation. You really must focus on what you are doing the entire time. There is no rushing, fussing, or mindlessness. And the relief of not messing it all up is an equally good feeling. While I’m certain processing will become easier over time, the fact remains that this careful work requires concentration and patience – two things I can always practice.